Typically, different types of electrical switches and receptacles are mounted on a plaster or mud ring which is bolted on the junction box. Because of different finished wall thicknesses, there are several sizes of plaster rings that have a protruded collar around their central opening where they receive the receptacles or switches. The protrusions must be raised to the thickness of the finished wall surface so that it would sit flush with the surface of the wall.
U.S. Pat. Pub. No. 2008/0035363 A1 to Yan, discloses an adjustable mud ring system that is somewhat adjustable by two screws on the back. However, adjusting the ring with the screws takes time and may not be sufficiently accurate due to mismatch of the level of adjustment of each screw.
The conventional systems of using fixed, one piece plaster rings, or rings adjustable by screws present a lot of difficulties and expenses where the finished material or thickness of the wall is not predictable. Furthermore, for the fixed, one piece rings, if future construction or remodeling is provisioned, the cost of removing the plaster ring is relatively high. Also, installing of the conventional systems takes a substantially long time due to the required adjustment for the wall thickness.
Therefore, there is a need for an improved and adjustable electrical junction box that can be effectively adjusted based on the thickness of the surface it is being installed on, and quickly installed.